Metal corrugated roofing sheets



Aug. 6, 1968 M. SEEFF 3,395,438

METAL CORRUGATED ROOFING SHEETS Filed Oct. 11, 1965 III- 'iklllhllln United States Patent 3,395,438 METAL CORRUGATED ROOFING SHEETS Morris Seetr, Johannesburg, Transvaal, Republic of South Africa, assignor to Steel Rolling Corporation (Africa) (Proprietary) Limited, Transvaal, Republic of South Africa Filed Oct. 11, 1965, Ser. No. 494,622 Claims priority, application Republic of South Africa, Oct. 21, 1964, 5,022 6 Claims. (Cl. 29-183) ABSTRACT OF THE DISCLOSURE A roofing sheet having corrugations or castellations therein with the top of the castellations extending in a curved plane and the bottom of the castellations extending in a curved plane parallel to the top curved plane and fiuttings in at least part of the bottom of the castellations extending at right angles to the lengths of the castellations.

This invention relates to metal roofing sheets of corrugated or castellated shape in which the spacing between adjacent corrugations or castellations is greater than the width of the corrugations or castellations.

Such sheets and in particular steel roofing sheets of castellated shape are often required in a curved shape the axis of curvature being at right angles to the axes of the castellations. When the sheets are curved in this way the portion placed under compression tend to wrinkle irregularly so that the sheet is unsightly. The wrinkles will thus form on the portions of the sheet between the castellations or on the tops of the castellations depending on the direction of curvature.

In accordance with this invention there is provided a curved roofing sheet of the type described in which at least part of the compressed portion of the sheet is regularly fluted in a direction at right angles to the lengths of the corrugations or castellations.

According to a further feature of the invention the flutings may have extensions of tapered shape formed in the sides of the castellations or corrugations.

A preferred embodiment of this invention is illustrated in the accompanying drawing which shows in perspective a short length of roofing material in accordance with this invention.

As shown, the invention is applied to a castellated roofing sheet 1 of normal type; the castellations 2 spaced apart at appreciably greater distances than the widths of the castellations 2.

If such a sheet 1 is longitudinally curved with the castellations 2 on the outside of the curve the portions 3 of the sheet between the castellations 2 and at the bases 4 of the latter will tend to wrinkle due to it being placed under compression.

This is avoided according to this invention by pressing flutings 5 into the sheet 1 between the castellations 2 which relieves the compressive stress on this portion of the sheet. The flutings 5 may be extended along the sides of the castellations 2 these extensions 6 tapering to meet the surfaces of the sides 7 of the castellations near the tops or crests 8 thereof and accordingly being deeper in the area under the greatest compressive stress.

The flutings 5 extend transversely to the lengths of the castellations and generally will not extend over the full length of the sheet. The area over which the flutings 5 "Ice extend is normally related to both the depth of the flutings and radius of curvature of the sheet 1. Thus the greater the radius of curvature the more flutings required and the greater the depths of the flutings the less flutings required.

The flutings are regularly spaced shaped so that they have an ornamental effect and may be of any suitable shape in cross-section but are preferably of spaced V- shapes in cross-section.

As these flutings will tend to hold rain water they are flattened along one or more narrow bands 9 extending parallel to the lengths of the castellations 2. These bands 9 allow for drainage of water over the curve and conveniently extend centrally between adjacent castellations 2 and/or adjacent the bottoms of the castellations 2.

If it is desired to curve the sheet in the opposite direction so that the castellations are on the inside of the curve the flutings are made on the compressed tops of the castellations and extended along the sides of the latter. As in the previously described structure the extensions of the flutings taper so that they are of maximum depth in the areas under greatest compressive stress.

Not only do the flutings relieve the compressive stress in the metal in the inside of the curve but also relieve the stresses ini the portions of metal which would normally be under a tensile stress.

The flutings are conveniently formed by a die assembly which forms a few flutings, for example a maximum of three at a time acrossthe width of the sheet and this method of forming the flutings is a feature of this invention. This method gives progressively sharper curvature as the number of pressing operations increase.

What I claim as new and desire to secure by Letters Patent is:

1. A roofing sheet comprising a metal sheet, castellations formed in said sheet and extending the full length thereof, the top of the castellations extending in an outer curved plane and the bottoms of the castellations extending in an inner curved plane parallel to said outer curved plane and regular flutings in at least part of the bottoms of the castellations extending at right angles to the lengths of the castellations.

2. A roofing sheet in accordance with claim 1 including indentations in the sides of the castellations said indentations extending and tapering from the bottoms of the castellations towards the tops thereof.

3. A roofing sheet in accordance with claim 1 including indentations in the sides of the castellations said indentations extending and tapering from the bottoms of the castellations towards the tops thereof and in which the depths of the indentations decrease from the bottoms of the castellations to the tops thereof.

4. A roofing sheet in accordance with claim 1 including narrow drainage bands in the bottoms of the castellations said bands formed by flattening portions of the flutings along lines extending parallel to the castellations.

5. A roofing sheet as claimed in claim 1 including a narrow drainage band located centrally in the width of the bottom of each castellation said bands formed by flattening portions of the flutings along lines extending parallel to the castellations.

6. A roofing sheet comprising a metal sheet, castellations formed in said sheet and extending the full length thereof, the top of the castellations extending in an outer curved plane and the bottoms of the castellations extending in an inner curved plane parallel to said outer curved plane, regularly spaced ornamental flutings in the bottoms of each castellation said flutings extending at right angles to the lengths of the castellations, indentations in the sides of the castellations said indentations extending and tapering from the bottoms of the castellations towards the tops thereof and the depths of the indentations decreasing from the bottoms of the castellations to the tops thereof, and narrow drainage bands in the bottoms of the castellations said bands formed by flattening portions of the fiutings along lines extending parallel to the castellations.

References Cited UNITED STATES PATENTS Ochiltree 52-630 Ashman 52-630 Bender 29183 Lebrun 52-573 RICHARD O. DEAN, Primary Examiner. 

